1. Field of the Invention
The present invention relates generally to lubricant coatings for hard disks for hard disk drives, and more particularly to devices and methods to suppress surface waves in a disk lubricant dipping tank.
2. Description of the Prior Art
Hard disks that are utilized in hard disk drives are typically coated with a thin lubrication film to protect the surface of the disk during usage. A common method for applying the lubrication film to the disks is by use of a lubrication tank in which the disks are submerged in a lubricant bath and slowly withdrawn from the bath. It is desirable that the thin lubrication film form a single uniform film coating on the surface of the disk for optimum disk drive performance at the disk magnetic head interface. However, it has been found that unwanted variations in the thickness of the thin lubricant film are typically created when the lubricant film is applied utilizing the disk dipping tank method.
A reason for the creation of unwanted multiple layers of lubricant upon portions of the disk surface is the existence of small surface waves within the lubricant bath as the disks are removed from the bath. These surface waves cause the meniscus at the intersection of the disk surface with the lubricant bath surface to rise and fall. With each such rising and falling of the meniscus a thickened lubricant line is applied to the surface of the disk. The lubricant is dispersed in a highly volatile carrier fluid which rapidly evaporates from the surface of the disk, such that the thickened lubricant line from the surface wave remains upon the disk surface.
The present invention provides a solution to this problem by minimizing the surface waves of the lubricant bath to create a more uniform lubricant coating upon the disk surface.